Systems and methods for controlling an evaporative cooling system

ABSTRACT

An evaporative cooling system may be employed in barns or other facilities that house animals to provide cooling and to reduce production loss. The control system for the evaporative cooling system may include circuitry designed to control pumping of water to a water storage facility used to supply water to evaporative cooling pads supply based on data received on inputs for controlling equipment and devices in the evaporative cooling system. The evaporative cooling control system may include a control circuit configured to determine whether or not evaporative cooling would be effective and operates pumps to supply water for the evaporative cooling system at times when that determination is positive and refrains from operating pumps when that determination is negative.

PRIORITY APPLICATION

This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 62/702,640 filed Jul. 24, 2018, entitled “HUMIDITY AND PH SENSOR,” the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND I. Field of the Disclosure

The technology of the disclosure relates generally to evaporative cooling systems and, more particularly, controlling water supply to evaporative cooling systems based on environmental conditions.

II. Background

An evaporative cooler or cooling system is a system that cools air through the evaporation of water. Evaporative cooling differs from typical air conditioning systems, which use vapor-compression or absorption refrigeration cycles. Evaporative cooling works by exploiting water's large enthalpy of vaporization. The temperature of dry air can be dropped significantly through the phase transition of liquid water to water vapor (evaporation). This can cool air using much less energy than refrigeration. In extremely dry climates, evaporative cooling of air has the added benefit of conditioning the air with more moisture for the comfort of building occupants.

Evaporative cooling systems can be particularly effective for cooling livestock to reduce heat stress and reduce production loss. Evaporative cooling is an indirect cooling method that utilizes air entering or inside a barn. The barn may be outfitted with evaporative cooling pads that work by pulling air through a media that is saturated with water. As the water is evaporated, it cools and humidifies the air entering the barn. This cool and humid air then increases convective heat loss from the animals in the barn compared to utilizing air at ambient conditions. Although requiring more equipment and management than a simple tunnel ventilation system, cooling pads offer the opportunity to both reduce heat stress on animals during the hot portion of the day and to cool the barn down quickly in the evening to allow for maximum recovery time for the animals.

Thus, evaporative cooling systems include a water supply to provide water to saturate the evaporative cooling pads. A water trough or tank may be employed to store water that is then pumped by a water pump(s) to the evaporative cooling pads for saturation. The water pumps require power to operate. Thus, energy is consumed each time the pumps are turned on to pump water to the evaporative cooling pads. Purchasing power from power companies to power such pumps adds to the overhead of such agricultural operations. It should be appreciated that such agricultural operations appreciate cost-saving opportunities.

SUMMARY OF THE DISCLOSURE

Aspects disclosed herein include evaporative cooling control systems for controlling water supply to evaporative cooling systems. An evaporative cooling system may be employed in barns or other facilities that house animals to provide cooling and to reduce production loss. The evaporative cooling control system may include a microprocessor, microcontroller, or other circuitry designed to control pumping of water with a supply pump to a water storage facility used to supply water to evaporative cooling pads based on data received on inputs for controlling equipment and devices in the evaporative cooling system. In exemplary aspects disclosed herein, the evaporative cooling control system includes a control circuit configured to determine whether or not evaporative cooling would be effective and operates pumps to supply water for the evaporative cooling system at times when that determination is positive and refrains from operating the pumps when that determination is negative.

In a first exemplary aspect, the evaporative cooling control system includes a control circuit configured to receive relative humidity information from a relative humidity sensor in the evaporative cooling control system indicating the relative humidity of the environment of the evaporative cooling system. If the relative humidity is less than a defined relative humidity set point (e.g., 70%), at which it is decided that evaporative cooling would be effective, the control circuit turns on the pump to pump water from a water storage facility to the evaporative cooling pads. When the relative humidity is greater than the defined relative humidity set point (e.g., 70%), where it has been decided that evaporative cooling would not be effective, the control circuit turns off the pump to discontinue pumping water from the water storage facility to the evaporative cooling pads. This conserves power and avoids overfilling the water storage facility when evaporative cooling would not be effective. Turning off the pump in this fashion can also reduce the saturation cycles of the evaporative cooling pads to extend their lives. It should be appreciated that temperature may also be considered when evaluating whether to operate the pump. For example, cooling may be effective but inappropriate at temperatures below approximately 75° F.

In another aspect, the evaporative cooling control system also includes one or more pH sensors in contact with the water supply in the water storage facility of the evaporative cooling system. The control circuit is configured to receive pH information regarding the pH level of the water supply for the evaporative cooling system. If evaporative cooling would not be effective, the control circuit may also determine the pH level of the water supply in the water storage facility for the evaporative cooling system, which can be an indication of contaminants in the water supply in the water storage facility. If the pH level of the water supply for the evaporative cooling system indicates an undesired level of contamination in the water supply, the control circuit can open a flush solenoid valve (“flush solenoid”) to allow water to drain from the water storage facility. The control circuit keeps open a fill solenoid valve (“fill solenoid”) to allow water from a primary water supply or primary water source to be supplied to the water storage facility, but the water in the water storage facility is drained through the flush solenoid. In this regard, in one aspect, the control circuit first turns on the supply pump to pre-pressurize the water storage facility in a flush operation. Then, the control circuit opens the flush solenoid to drain the water from the water storage facility such that the water does not reach the evaporative cooling pads. Once the pH level of the water supply for the evaporative cooling system does not indicate an undesired level of contamination in the water storage facility, the control circuit can close the flush solenoid to discontinue draining of water from the water storage facility.

As an alternative to the pH sensor, a flush may be done periodically without reference to a specific contamination level. The period may be set below an empirically derived timeframe in which contamination is likely to occur or by other means as needed or desired.

In this manner, when evaporative cooling is not effective, the control circuit turns off the pump to avoid the need to consume power to pump water to the evaporative cooling pads, which can also extend the lives of the evaporative cooling pads. If evaporative cooling is deemed not effective, the control circuit can ensure that the water supply in the water storage facility is maintained at a desired contaminant level and flush the water supply if above a desired contaminant level. In one example, flushing of the water supply is performed when evaporative cooling is not effective, so that the flushing operation does not affect supplying water to the evaporative cooling pads when such would be needed to maintain cooling, such as for animals.

One embodiment is a control circuit for controlling an evaporative cooling system. The control circuit is configured to receive an input signal indicating a relative humidity of ambient air of an environment associated with the evaporative cooling system as measured by a relative humidity sensor. The control circuit is also configured to compare the relative humidity as measured by the relative humidity sensor to a defined humidity threshold from a humidity threshold setting. When the relative humidity as measured by the relative humidity sensor is below the defined humidity threshold, the control circuit is configured to generate an output signal to cause a pump to pump water from a water storage facility to evaporative cooling pads in the evaporative cooling system.

A further embodiment includes a method for controlling an evaporative cooling system. The method includes receiving an input signal at a control circuit, the input signal indicating a relative humidity of ambient air of an environment associated with the evaporative cooling system as measured by a relative humidity sensor. The method also includes comparing, with the control circuit, the relative humidity as measured by the relative humidity sensor to a defined humidity threshold from a humidity setting. The method also includes, when the relative humidity as measured by the relative humidity sensor is below the defined humidity threshold, generating an output signal from the control circuit to cause a pump to pump water from a water storage facility to evaporative cooling pads in the evaporative cooling system.

A further embodiment includes a method for controlling an evaporative cooling system. The method includes receiving an input signal at a control circuit, the input signal indicating an amount of light within an environment associated with the evaporative cooling system as measured by a photocell. The method also includes comparing, with the control circuit, the amount of light as measured by the photocell to a defined threshold. The method also includes, when the amount of light as measured by the photocell is indicative of daytime, generating an output signal from the control circuit to cause a pump to pump water from a water storage facility to evaporative cooling pads in the evaporative cooling system.

A further embodiment includes an evaporative cooling system. The evaporative cooling system includes a sensor including at least one of a photocell or a relative humidity sensor. The evaporative cooling system also includes a water pump configured to pump water from a water storage facility to evaporative cooling pads. The evaporative cooling system also includes a control circuit coupled to the sensor and the water pump. The control circuit is configured to receive an input signal from the sensor. Based on the input signal from the sensor, the control circuit is configured to determine if a sensor threshold is met. When the sensor threshold is met, the control circuit is configured to generate an output signal to cause the water pump to pump water from the water storage facility to the evaporative cooling pads.

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of an evaporative cooling control circuit that is configured to control a water pump that is configured to pump water to evaporative cooling pads in an evaporative cooling system as a function of relative humidity and/or pH level of the water supply;

FIG. 1B is schematic of an alternate evaporative cooling circuit that is configured to control a water pump that is configured to pump water to evaporative cooling pads in an evaporative cooling system as a function of temperature, relative humidity and time;

FIG. 2A is an exemplary flowchart illustrating an exemplary process associated with an evaporative cooling system according to exemplary aspects of the present disclosure;

FIG. 2B is an exemplary flowchart illustrating an alternate process associated with an evaporative cooling system according to exemplary aspects of the present disclosure;

FIG. 3 is an exemplary flowchart illustrating a more detailed logic path reflecting exemplary operation of the evaporative cooling control circuit in FIG. 1;

FIG. 4 illustrates tables that contain an exemplary list of inputs and outputs to the evaporative cooling control circuit in FIG. 1 and the control logic implemented by the control circuit; and

FIG. 5 is a schematic diagram of an exemplary evaporative cooling control system control module that houses the control circuit and includes inputs receiving environmental information and outputs for issuing commands to control devices in an evaporative cooling system.

DETAILED DESCRIPTION

With reference now to the drawing figures, several exemplary aspects of the present disclosure are described. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

Aspects disclosed herein include evaporative cooling control systems for controlling water supply to evaporative cooling systems. An evaporative cooling system may be employed in barns or other facilities that house animals to provide cooling and to reduce production loss. The evaporative cooling control system may include a microprocessor, microcontroller or other circuitry designed to control pumping of water with a supply pump to a water storage facility used to supply water to evaporative cooling pads based on data received on inputs for controlling equipment and devices in the evaporative cooling system. In exemplary aspects disclosed herein, the evaporative cooling control system includes a control circuit configured to determine whether or not evaporative cooling would be effective and operates pumps to supply water for the evaporative cooling system at times when that determination is positive and refrains from operating the pumps when that determination is negative.

In a first exemplary aspect, the evaporative cooling control system includes a control circuit configured to receive relative humidity information from a relative humidity sensor in the evaporative cooling control system indicating the relative humidity of the environment of the evaporative cooling system. If the relative humidity is less than a defined relative humidity set point (e.g., 70%), at which it is decided that evaporative cooling would be effective, the control circuit turns on the pump to pump water from a water storage facility to the evaporative cooling pads. When the relative humidity is greater than the defined relative humidity set point (e.g., 70%), where it has been decided that evaporative cooling would not be effective, the control circuit turns off the pump to discontinue pumping water from the water storage facility to the evaporative cooling pads. This conserves power and avoids overfilling the water storage facility when evaporative cooling would not be effective. Turning off the pump in this fashion can also reduce the saturation cycles of the evaporative cooling pads to extend their lives.

In another aspect, the evaporative cooling control system also includes one or more pH sensors in contact with the water supply in the water storage facility of the evaporative cooling system. The control circuit is configured to receive pH information regarding the pH level of the water supply for the evaporative cooling system. If evaporative cooling would not be effective, the control circuit may also determine the pH level of the water supply in the water storage facility for the evaporative cooling system, which can be an indication of contaminants in the water supply in the water storage facility. If the pH level of the water supply for the evaporative cooling system indicates an undesired level of contamination in the water supply, the control circuit can open a flush solenoid valve (“flush solenoid”) to allow water to drain from the water storage facility. The control circuit keeps open a fill solenoid valve (“fill solenoid”) to allow water from a primary water supply or primary water source to be supplied to the water storage facility, but the water in the water storage facility is drained through the flush solenoid. In this regard, in one aspect, the control circuit first turns on the supply pump to pre-pressurize the water storage facility in a flush operation. Then, the control circuit opens the flush solenoid to drain the water from the water storage facility such that the water does not reach the evaporative cooling pads. Once the pH level of the water supply for the evaporative cooling system does not indicate an undesired level of contamination in the water storage facility, the control circuit can close the flush solenoid to discontinue draining of water from the water storage facility.

In this manner, when evaporative cooling is not effective, the control circuit turns off the pump to avoid the need to consume power to pump water to the evaporative cooling pads, which can also extend the lives of the evaporative cooling pads. If evaporative cooling is deemed not effective, the control circuit can ensure that the water supply is maintained at a desired contaminant level and flush the water supply in the water storage facility if above a desired contaminant level. In one example, flushing of the water supply is performed when evaporative cooling is not effective, so that the flushing operation does not affect supplying water to the evaporative cooling pads when such would be needed to maintain cooling, such as for animals.

In this regard, FIG. 1A is a schematic diagram of an exemplary evaporative cooling control system 100. The evaporative cooling control system 100 in this example includes a main control circuit 102 and a secondary control circuit 104 that include a controller, microprocessor, microcontroller, or other circuit coupled to inputs for receiving input signals coupled to devices indicating information regarding an evaporative cooling system. The main control circuit 102 and the secondary control circuit 104 are also coupled to outputs to direct output signals to devices to control the operation of the evaporative cooling system and, in particular, the supply of water to evaporative cooling pads or other evaporative cooling element. As will be discussed by example in more detail below, the main control circuit 102 and the secondary control circuit 104 are configured to control a water pump in an evaporative cooling system to pump water to evaporative cooling pads in the evaporative cooling system as a function of relative humidity. As will also be discussed by example in more detail below, the main control circuit 102 and secondary control circuit 104 are also configured to flush the water in the water storage facility with fresh water from a water source if the pH level of the water supply indicates a contamination level beyond a desired level. The main control circuit 102 will first be discussed below. The secondary control circuit 104 is optional.

With reference to FIG. 1A, the main control circuit 102 includes a humidity input 106 coupled to a relative humidity sensor 110. The main control circuit 102 is configured to receive an input signal 108 over the humidity input 106 indicating relative humidity measured by the relative humidity sensor 110. The main control circuit 102 also includes a pH input 112 coupled to a pH sensor 114. The main control circuit 102 is configured to receive an input signal 116 over the pH input 112 indicating a pH level measured by the pH sensor 114. The main control circuit 102 also includes a high water level input 118 coupled to a high water level sensor 120 (“high float sensor 120”), which is a float switch in this example, associated with a water storage facility for the evaporative cooling system. The main control circuit 102 is configured to receive an input signal 122 indicating whether a water level in the water storage facility for the evaporative cooling is at a designated high water level. The main control circuit 102 also includes a low water level input 124 coupled to a low water level sensor 126 (“low float sensor 126”), which is also a float switch in this example, associated with the water storage facility for the evaporative cooling system. The main control circuit 102 is configured to receive an input signal 128 indicating whether the water level in the water storage facility for the evaporative cooling system is at a designated low water level.

With continuing reference to FIG. 1A, the main control circuit 102 also includes a timer output 130 coupled to a timer logic 132. The main control circuit 102 is configured to generate an alternating current (AC) output signal 136 to provide power to a pump 138. The main control circuit 102 is also configured to generate an output signal 134 to the timer logic 132 to set the timer logic 132, such that the timer logic 132 is configured to control the on/off cycling of the pump 138 instead of the pump 138 being continuously operational. The main control circuit 102 also includes a fill output 140 coupled to a fill solenoid valve 142 (“fill solenoid 142”) associated with the water storage facility. The main control circuit 102 is configured to generate an output signal 144 to the fill solenoid 142 to control the opening and closing of the fill solenoid 142 to either allow fresh water from an external source (e.g., a water supply) to introduce new water into the water storage facility or to block fresh water from being introduced into the water storage facility. In this example, the pump 138 does not control the pumping of new water into the water storage facility, and a pump is not required. However, there may be a supply pump (not shown) which is activated concurrently with the fill solenoid 142 to assist in filling the water storage facility (e.g., to pre-pressurize the water storage facility). The main control circuit 102 also includes a flush output 146 coupled to a flush solenoid valve 148 (“flush solenoid 148”) associated with the water storage facility. The main control circuit 102 is configured to generate an output signal 150 to the flush solenoid 148 to control the opening and closing of the flush solenoid 148 to control if water in the water storage facility is allowed to drain. The main control circuit 102 also includes an alarm output 152 coupled to an evaporative cooling system control circuit 154. The main control circuit 102 is configured to generate an alarm signal 156 to the evaporative cooling system control circuit 154 to indicate if the main control circuit 102 has experienced an alarm. The evaporative cooling system control circuit 154 may generate other alarms and/or take other actions to control the evaporative cooling system based on an alarm condition indicated by the alarm signal 156.

Note that a flush indicator and fill indicator, such as LED lights, may also be associated with the flush solenoid 148 and the fill solenoid 142, so that a visual indicator is provided when the flush and fill operation cycles are active and inactive.

While the evaporative cooling system 100 is adequate for many installations, there may be reasons where a pH sensor is impractical to sense contamination of the water storage facility. A timer may be used to flush the water storage facility periodically to prevent contamination levels from rising too high. Likewise, it may be appropriate to add a temperature sensor or accommodate a temperature sensor when determining if evaporative cooling would be effective. For example, it may be inappropriate to cool an environment if the ambient temperature is below 50° F. Likewise, while evaporative cooling may be effective below 75° F., it may still be unnecessary to provide cooling at those temperatures.

In this regard, FIG. 1B illustrates an evaporative cooling control system 100A which is substantially similar to the evaporative cooling control system 100 of FIG. 1A, but the main control circuit 102A has, instead of the pH input 112, a temperature input 180 which receives a temperature signal 182 from a temperature sensor 184. This signal may be passed to the secondary control circuit 104A, which receives the temperature signal 182 at a temperature input 180S.

In addition to the temperature sensor 184, the main control circuit 102A may include a timer 186 which controls the fill and flush cycles as better explained below with reference to FIG. 2B.

Note that the main control circuit 102 of FIG. 1A may also have an input (not shown) for temperature, which may gate whether any evaporative cooling takes place (regardless of humidity or pH).

FIG. 2A provides a generalized process 200 associated with the evaporative cooling control system 100 of FIG. 1. In particular, the process 200 begins by using a sensor to take a measurement (block 202). This sensor may be the relative humidity sensor 110, a daylight sensor such as photocell 510 (FIG. 5), or some other sensor as appropriate. Based on the sensor, a control system such as the main control circuit 102 may determine if evaporative cooling will be effective (block 204). If the answer to block 204 is yes, then the main control circuit 102 may turn the pump 138 on or leave the pump 138 running (block 206) while continuing to monitor with the sensor (block 202).

If, however, the answer to block 204 is no, evaporative cooling would not be effective, then the main control circuit 102 may turn the pump 138 off or leave the pump 138 off (block 208). While the pump 138 is off, the process 200 may further test for contamination of the water storage facility (block 210). Such test may be performed with a contamination sensor such as the pH sensor 114. Based on the results of the test at block 208, the main control circuit 102 may determine if the water in the water storage facility is contaminated (block 212). If the answer is no, then the process 200 returns and monitors at block 202. If, however, the answer to block 212 is yes, the water is contaminated, then the main control circuit 102 may initiate a flush (block 214) and refill of the water storage facility (block 216) before returning to monitoring at block 202.

FIG. 2B illustrates an alternate process 250 that contemplates temperature control and a periodic flush instead of a specific test for contamination. In this regard, the process 250 starts with a determination if the temperature is above a predefined threshold (block 252). In an exemplary aspect, the predefined threshold may be 75° F., although other temperatures may be used. If the answer is no, then no evaporative cooling takes place because the evaporative cooling may be ineffective. In a first aspect, the process loops at block 252 until the predefined threshold is passed and block 252 is answered affirmatively. Alternatively, the process 250 may skip to block 254 as described below.

If the answer to block 252 is yes, the temperature is above the predefined threshold, there may be an initial signal to turn on the pump 138. However, this signal may be gated by the remainder of the process 250. That is, the process 250 continues by using a sensor to take a measurement (block 202). This sensor may be the relative humidity sensor 110, a daylight sensor such as photocell 510 (FIG. 5), or some other sensor as appropriate. Based on the sensor, a control system such as the main control circuit 102 or main control circuit 102A may determine if evaporative cooling will be effective (block 204). If the answer to block 204 is yes, then the main control circuit 102 may allow the pump signal generated at block 250 to pass through which may turn the pump 138 on or leave the pump 138 running (block 206) while continuing to monitor with the sensor (block 202).

If, however, the answer to block 204 is no, evaporative cooling would not be effective, then the main control circuit 102 may turn the pump 138 off or leave the pump 138 off (block 208).

Instead of testing for contamination, the main control circuit 102A may turn on a timer 186 (block 254) (or leave it on if the timer is already on) and test to see if the timer 186 has expired (block 256). If the answer to block 256 is no, then the process 250 returns and monitors at block 252. If, however, the answer to block 256 is yes, the timer 186 has expired, then the main control circuit 102A may initiate a flush (block 214) and refill of the water storage facility (block 216) before returning to monitoring at block 252. Note that the flushing based on the timer 186 may operate independently of the temperature and/or relative humidity or the flushing may be integrated as illustrated in FIG. 2B.

FIG. 3 is a more detailed flowchart illustrating an exemplary operation process 300 of the evaporative cooling control system 100 in FIG. 1. In particular, some decision points that are generalized in the process 200 are more explicitly set forth. In this example, the main control circuit 102 of the evaporative cooling control system 100 is configured to perform the process 300 in FIG. 3. The process 300 is a looping process that starts after a power reset of the main control circuit 102 (block 302). Thereafter, the main control circuit 102 checks the relative humidity of the outside environment of the evaporative cooling system based on the input signal 108 received on the humidity input 106 indicating the relative humidity measured by the relative humidity sensor 110 (block 304) by comparing the relative humidity as measured by the relative humidity sensor 110 to a defined humidity threshold. This check is performed first in this example, because it was determined as a design consideration to first check to see if the evaporative cooling system would be effective even if operated by pumping water to the evaporative cooling pads. If the relative humidity is below a defined, programmed set humidity threshold setting (e.g., the defined humidity threshold may be 70% or other predefined relative humidity) (block 306), the evaporative cooling system is deemed to be effective. The main control circuit 102 generates the output signal 136 to turn on the pump 138 of the evaporative cooling system to pump water from the water storage facility to the evaporative cooling pads (block 308). Note that the output signal 136 may not be a signal per se, but could, instead be a gate that gates a signal generated by a temperature sensor (e.g., the sensor 184) to turn on the pump 138. The main control circuit 102 then checks to see, based on the input signal 122, whether the water level in the water storage facility of the evaporative cooling system is at a designated high water level, meaning full (block 310). If the water level in the water storage facility is detected at the high water level (block 312), the main control circuit 102 generates the output signal 144 to close the fill solenoid 142 to discontinue introducing new water into the water storage facility (block 314), and the main control circuit 102 checks the relative humidity (block 304). If the water level in the water storage facility is not detected at the high water level (block 312), the main control circuit 102 generates the output signal 144 to open the fill solenoid 142 so that new water is introduced into the water storage facility to allow the water storage facility to fill (block 315) until the high water level is again detected (block 310).

With continuing reference to FIG. 3, if the relative humidity is above the set humidity threshold setting (e.g., 70%) (block 306), the evaporative cooling system is deemed to not be effective. The main control circuit 102 generates the output signal 136 to turn off the pump 138 of the evaporative cooling system to discontinue pumping water from the water storage facility to the evaporative cooling pads (block 316). The main control circuit 102 then checks the pH level of the water in the water storage facility based on the input signal 116 (also referred to as a pH input signal) from the pH sensor 114 (block 318). If the pH level is less than a defined pH level (sometimes referred to as a pH threshold, e.g., 9) (block 320), the water in the water storage facility is considered to not be contaminated, and the process goes to block 314 to continue to keep the fill solenoid 142 closed (block 314) and the relative humidity level is checked again (block 304). If however, the pH level is greater than the defined pH level (e.g., 9) (block 320), the water in the water storage facility is considered to be contaminated. The main control circuit 102 generates the output signal 150 on the flush output 146 to cause the flush solenoid 148 to open to allow the water in the water storage facility to start to drain (block 322). The main control circuit 102 generates the output signal 136 to turn on the pump 138 of the evaporative cooling system to pump new (i.e., fresh) water into the water storage facility (block 324). The main control circuit 102 then checks to see, based on the input signal 128 (sometimes referred to as a low water level input signal), whether the water level in the water storage facility of the evaporative cooling system is at a designated low water level, meaning the water has sufficiently drained without being refilled (block 325). If the water level in the water storage facility is detected at the low water level (block 326), the main control circuit 102 continues to generate the output signal 150 on the flush output 146 to cause the flush solenoid 148 to open (block 322) and generate the output signal 136 to turn on the water pump 138 (block 324).

With continuing reference to FIG. 3, once the water level in the water storage facility is no longer detected at the low water level (block 326), the main control circuit 102 generates the output signal 136 to turn off the pump 138 of the evaporative cooling system (block 328) and generates the output signal 150 on the flush output 146 to cause the flush solenoid 148 to close, to allow the water in the water storage facility to stop draining (block 330). The main control circuit 102 then checks to see based on the input signal 122 (sometimes referred to as a high water level input signal) whether the water level in the water storage facility of the evaporative cooling system is at a designated high water level, meaning full (block 332). If water level in the water storage facility is detected at the high water level (block 334), the flush cycle is complete and the water storage facility is full and the process 300 returns to block 314. If however, the water level in the water storage facility is not detected at the high water level (block 334), this means the water storage facility is not yet full. The main control circuit 102 generates the output signal 144 to open the fill solenoid 142 so that the new water is introduced into the water storage facility and is not drained thus allowing the water storage facility to fill (block 336). The main control circuit 102 then checks to verify, based on the input signal 128, whether the water level in the water storage facility of the evaporative cooling system is at a designated low water level (block 338). If the water level in the water storage facility is at the low water level (block 340), the process returns back to block 332. If the water level in the water storage facility is not at the low water level (block 340), the main control circuit 102 generates the output signal 134 to initiate the timer logic 132 (block 342) and wait a time delay (block 343). If the timer logic 132 has not expired (block 344), the main control circuit 102 then generates the output signal 150 to keep the flush solenoid 148 open (block 348) with a repeat of the loop of blocks 332-340. If the high water level is not detected (block 334) before the timer logic 132 expires (block 344), this means the water storage facility is not filling properly and an alarm is generated (block 346).

If the relative humidity sensor 110 or pH sensor 114 fails, the system may include a fail safe operation mode wherein the main control circuit 102 continues to operate the water pump 138. Such continued operation causes water to continue to be pumped to the evaporative cooling pads so that the evaporative cooling continues.

With reference back to FIG. 1, note that the secondary control circuit 104 previously introduced can also be provided. The secondary control circuit 104 can be provided to control a secondary water storage facility if provided in the evaporative cooling control system 100. A second, main control circuit 102 and associated devices could be provided. But since relative humidity may be the same in the evaporative cooling control system 100 irrespective of whether a second water storage facility is provided, and also because the pH level measured in one water storage facility may be used as an indirect indication of water quality in the second water storage facility, it may not be necessary to provide an additional relative humidity sensor 110 and pH sensor 114. These sensors can be shared. In this regard, the secondary control circuit 104 includes the same components and features as the main control circuit 102, but is shown with a suffix of ‘S’ in FIG. 1 and thus will not be re-described. Also, the secondary control circuit 104 can perform the same processes in FIGS. 2 and 3. However, in this example, as shown in FIG. 1, the input 106S and input 112S are coupled to the outputs 160, 162 of the main control circuit 102 that are short circuited to the humidity input 106 and the pH input 112 to the relative humidity sensor 110 and pH sensor 114. Thus, the same input signals 108, 116 can be coupled to the inputs 106S, 112S of the secondary control circuit 104 to allow the secondary control circuit 104 to detect relative humidity and pH level for cost savings. The main control circuit 102 and secondary control circuit 104 include alarm combining circuits 164, 164S so that an alarm generated by either the main control circuit 102 or the secondary control circuit 104 will cause the other, the secondary control circuit 104 or the main control circuit 102, to generate a respective alarm signal 156, 156S to the evaporative cooling system control circuit 154.

FIG. 4 illustrates tables that contain an exemplary list of inputs 400 and outputs 402 to the main control circuit 102 in FIG. 1 and the control logic implemented by the control circuit. The same control logic is applicable also to the secondary control circuit 104 in FIG. 1. As illustrated, the inputs come from the sensors 110, 114, 120, 126, and 132 as well as a count. The outputs are the signals to the water pump 138, the fill solenoid 142, the flush solenoid 148, and the alarm output 152 as well as a visual flush indicator.

Thus, the water pump 138 is on at 404 when either relative humidity is less than the set point AND the on/off timer (OFT) is ON (i.e., evaporative cooling is effective and the timer has not expired) OR relative humidity is greater than the set point AND the pH level is greater than the set point (i.e., there is no cooling and the water needs to be flushed).

The water supply storage is being filled by having the fill solenoid 142 ON at 406 when relative humidity is less than the set point AND the high float sensor 120 is OFF (i.e., the tank is low and it needs water to run the evaporative cooling) OR relative humidity is greater than the set point AND the pH level is greater than the set point AND the low float sensor 126 is OFF (i.e., evaporative cooling is not effective, the water is contaminated and the water level is low).

The flush is activated at 408 when relative humidity is above the set point AND the pH level is above the set point AND, the low float sensor 126 is ON (i.e., evaporative cooling is not effective, the water is contaminated, and the water level is high enough to support a flush).

The alarm is activated at 410 when the high float sensor 120 is OFF AND the low float sensor 126 is OFF AND, the counter is above the set point (i.e., the water level is fine, but the counter has expired).

The flush is also activated at 412 when the high float sensor 120 is OFF AND the low float sensor is OFF AND, the counter is above the set point (i.e., the water level is fine, but the counter has expired (e.g., the water is just stale)).

FIG. 5 is a schematic diagram of an alternative exemplary evaporative cooling control circuit 500 that is similar to the main control circuit 102 in FIG. 1, except that a relative humidity sensor is not provided, and thus, relative humidity is not checked. The control circuit 500 also includes a pH input 502 coupled to a pH sensor 504. The control circuit 500 is configured to receive a pH signal 506 over the pH input 502 indicating pH levels measured by the pH sensor 504. The control circuit 500 also includes a photocell input 508 coupled to a photocell 510 to detect an amount of light (i.e., day or night) based on a photocell signal 512 received on the photocell input 508. The control circuit 500 also includes a pump output 514 coupled to a water pump 516. The control circuit 500 is configured to generate an output signal 518 to control turning on and off the water pump 516 of the evaporative cooling system for controlling the pumping of water to the evaporative cooling pads. The control circuit 500 also includes a notification output 520 coupled to a notification indicator 522 (i.e., a light). The control circuit 500 is configured to generate an output signal 524 to the notification indicator 522. The same process operations described in FIGS. 2 and 3 can be employed by the control circuit 500, wherein the photocell signal 512 indicating day or light above a defined threshold is used in place of the relative humidity being less than a humidity set point to trigger the water pump 516 to be turned on in block 308. The pH signal 506 can be used to check the pH level in block 320 in FIG. 3. The control circuit 500 in this example is able to turn on the water pump 516 during the day and off during the night based on the photocell signal 512, and turn on the notification indicator 522 if the water quality indicates contamination levels are too high based on the pH signal 506 so that a manual flush and fill operation can be performed.

It should be appreciated that generically, a sensor input (e.g., the input from the relative humidity sensor 110 or the photocell 510) is compared to a sensor threshold to see if the evaporative cooling would be effective. Likewise, water contamination is tested through a pH measurement, and if a threshold is exceeded, the water in the water storage facility is flushed. Flushing and filling of the water storage facility is controlled by the flush/fill solenoids and monitored by water level sensors. If a flush or fill does not operate in a desired manner, an alarm may be generated.

Those of skill in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithms described in connection with the aspects disclosed herein may be implemented as electronic hardware, instructions stored in memory or in another computer readable medium and executed by a processor or other processing device, or combinations of both. The master and slave devices described herein may be employed in any circuit, hardware component, integrated circuit (IC), or IC chip, as examples. Memory disclosed herein may be any type and size of memory and may be configured to store any type of information desired. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. How such functionality is implemented depends upon the particular application, design choices, and/or design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

The aspects disclosed herein may be embodied in hardware and in instructions that are stored in hardware, and may reside, for example, in Random Access Memory (RAM), flash memory, Read Only Memory (ROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk, a removable disk, a CD-ROM, or any other form of computer readable medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a remote station. In the alternative, the processor and the storage medium may reside as discrete components in a remote station, base station, or server.

It is also noted that the operational steps described in any of the exemplary aspects herein are described to provide examples and discussion. The operations described may be performed in numerous different sequences other than the illustrated sequences. Furthermore, operations described in a single operational step may actually be performed in a number of different steps. Additionally, one or more operational steps discussed in the exemplary aspects may be combined. It is to be understood that the operational steps illustrated in the flowchart diagrams may be subject to numerous different modifications as will be readily apparent to one of skill in the art. Those of skill in the art will also understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. 

What is claimed is:
 1. A control circuit for controlling an evaporative cooling system, the control circuit configured to: receive an input signal indicating a relative humidity of ambient air of an environment associated with the evaporative cooling system as measured by a relative humidity sensor; compare the relative humidity as measured by the relative humidity sensor to a defined humidity threshold from a humidity threshold setting; and when the relative humidity as measured by the relative humidity sensor is below the defined humidity threshold, generate an output signal to cause a pump to pump water from a water storage facility to evaporative cooling pads in the evaporative cooling system.
 2. The control circuit of claim 1, further configured to: when the relative humidity as measured by the relative humidity sensor is above the defined humidity threshold: receive a second input signal generated by a high water level sensor coupled to the water storage facility indicating a water level of the water storage facility; and in response to the second input signal indicating the water level is at or above a designated high water level, generate a second output signal to close a fill solenoid to discontinue introducing new water into the water storage facility.
 3. The control circuit of claim 2, further configured to, in response to the second input signal indicating the water level is below the designated high water level, generate a third output signal to open the fill solenoid so that new water is introduced into the water storage facility.
 4. The control circuit of claim 1, further configured to: receive a pH input signal generated by a pH sensor associated with the water storage facility indicating a pH of the water within the water storage facility.
 5. The control circuit of claim 4, further configured to: in response to a determination that the pH of the water within the water storage facility is below a pH threshold as indicated by the pH input signal, generate a second output signal to close a fill solenoid to discontinue introducing new water into the water storage facility.
 6. The control circuit of claim 4, further configured to: in response to a determination that the pH of the water within the water storage facility is above a pH threshold as indicated by the pH input signal, generate a third output signal to open a flush solenoid; and generate a fourth output signal to turn on the pump.
 7. The control circuit of claim 6, further configured to: receive a low water level input signal; and in response to a determination that the water within the water storage facility is below a designated low water level, generate a fifth output signal to turn off the pump; and generate a sixth output signal to close the flush solenoid.
 8. The control circuit of claim 6, further configured to receive a low water level input signal; and in response to a determination that the water within the water storage facility is at or above a designated low water level, leave the flush solenoid open and leave the pump on.
 9. The control circuit of claim 4, further configured to: receive a low water level input signal; and in response to a determination that the water within the water storage facility is below a designated low water level, generate a fifth output signal to turn off the pump; and generate a sixth output signal to close a flush solenoid.
 10. The control circuit of claim 6, further configured to: receive a second input signal generated by a high water level sensor coupled to the water storage facility indicating a water level of the water storage facility; and in response to the second input signal indicating the water level is at or above a designated high water level, generate a second output signal to close a fill solenoid to discontinue introducing new water into the water storage facility.
 11. The control circuit of claim 6, further configured to: receive a high water level input signal generated by a high water level sensor coupled to the water storage facility indicating a water level of the water storage facility; in response to the high water level input signal indicating the water level is below a designated high water level, generate a second output signal to open a fill solenoid to introduce new water into the water storage facility.
 12. The control circuit of claim 1, further comprising a temperature input configured to receive a temperature signal from a temperature sensor, wherein the control circuit is further configured to control the pump based at least in part on the temperature signal.
 13. The control circuit of claim 1, further comprising a timer, wherein the control circuit is configured to cause the water storage facility to flush at expiration of the timer.
 14. The control circuit of claim 13, wherein the control circuit is configured to send a signal to open a flush solenoid to begin flushing the water storage facility.
 15. A method for controlling an evaporative cooling system, the method comprising: receiving an input signal at a control circuit, the input signal indicating a relative humidity of ambient air of an environment associated with the evaporative cooling system as measured by a relative humidity sensor; comparing, with the control circuit, the relative humidity as measured by the relative humidity sensor to a defined humidity threshold from a humidity threshold setting; and when the relative humidity as measured by the relative humidity sensor is below the defined humidity threshold, generating an output signal from the control circuit to cause a pump to pump water from a water storage facility to evaporative cooling pads in the evaporative cooling system.
 16. The method of claim 15, further comprising: when the relative humidity as measured by the relative humidity sensor is above the defined humidity threshold: receiving a second input signal generated by a high water level sensor coupled to the water storage facility indicating a water level of the water storage facility; in response to the second input signal indicating the water level is at or above a designated high water level, generating a second output signal to close a fill solenoid to discontinue introducing new water into the water storage facility.
 17. The method of claim 16, further comprising: in response to the second input signal indicating the water level is below the designated high water level, generating a third output signal to open the fill solenoid so that new water is introduced into the water storage facility.
 18. The method of claim 15, further comprising receiving a pH input signal generated by a pH sensor associated with the water storage facility indicating a pH of the water within the water storage facility.
 19. The method of claim 18, further comprising: in response to a determination that the pH of the water within the water storage facility is below a pH threshold as indicated by the pH input signal, generating a second output signal to close a fill solenoid to discontinue introducing new water into the water storage facility.
 20. The method of claim 18, further comprising: in response to a determination that the pH of the water within the water storage facility is above a pH threshold as indicated by the pH input signal, generating a third output signal to open a flush solenoid; and generating a fourth output signal to turn on the pump.
 21. A method for controlling an evaporative cooling system, the method comprising: receiving an input signal at a control circuit, the input signal indicating an amount of light within an environment associated with the evaporative cooling system as measured by a photocell; comparing, with the control circuit, the amount of light as measured by the photocell to a defined threshold; and when the amount of light as measured by the photocell is indicative of daytime, generating an output signal from the control circuit to cause a pump to pump water from a water storage facility to evaporative cooling pads in the evaporative cooling system.
 22. An evaporative cooling system, comprising: a sensor comprising at least one of a photocell or a relative humidity sensor; a water pump configured to pump water from a water storage facility to evaporative cooling pads; and a control circuit coupled to the sensor and the water pump, the control circuit configured to: receive an input signal from the sensor; based on the input signal from the sensor, determine if a sensor threshold is met; and when the sensor threshold is met, generate an output signal to cause the water pump to pump water from the water storage facility to the evaporative cooling pads.
 23. The evaporative cooling system of claim 22, further comprising a second water pump and a second control circuit, the second control circuit configured to: receive the input signal from the sensor; based on the input signal from the sensor, determine if the sensor threshold is met; and when the sensor threshold is met, generate a second output signal to cause the second water pump to pump water from a second water storage facility to second evaporative cooling pads. 